Abstract
Electrical impedance tomography (EIT) is able to detect rapid lung volume changes during breathing. The aim of our observational study was to characterise the heterogeneity of regional ventilation distribution in lung-healthy adults by EIT and to detect the possible impact of tobacco consumption.
A total of 219 nonsmokers, asymptomatic ex-smokers and current smokers were examined during forced full expiration using EIT. Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC were determined in 836 EIT image pixels for the analysis of spatial and temporal ventilation distribution. Coefficients of variation (CVs) of these pixel values were calculated. Histograms and medians of FEV1/FVCEIT and times required to exhale 50%, 75%, 90% of FVCEIT (t50, t75 and t90) were generated.
CV of FEV1/FVCEIT distinguished among all groups (mean±sd: nonsmokers 0.43±0.05, ex-smokers 0.52±0.09, smokers 0.62±0.16). Histograms of FEV1/FVCEIT differentiated between nonsmokers and the other groups (p<0.0001). Medians of t50, t75 and t90 showed the lowest values in nonsmokers. Median t90 separated all groups (median (interquartile range): nonsmokers 0.82 (0.67–1.15), ex-smokers 1.41 (1.03–2.21), smokers 1.91 (1.33–3.53)).
EIT detects regional ventilation heterogeneity during forced expiration in healthy nonsmokers and its increase in asymptomatic former and current smokers. Therefore, EIT-derived reference values should only be collected from nonsmoking lung-healthy adults.
Abstract
EIT assesses the spatial and temporal distribution of lung function in adults without pulmonary disease, and detects its increased heterogeneity in former and current smokers compared with nonsmokers. EIT reference values should originate from nonsmokers. http://bit.ly/2wsJQWD
Footnotes
Conflict of interest: B. Vogt reports grants from the European Commission outside the submitted work.
Conflict of interest: K. Deuß has nothing to disclose.
Conflict of interest: V. Hennig has nothing to disclose.
Conflict of interest: Z. Zhao reports a consulting fee from Dräger Medical AG outside the submitted work.
Conflict of interest: I. Lautenschläger has nothing to disclose.
Conflict of interest: N. Weiler has nothing to disclose.
Conflict of interest: I. Frerichs report grants from the European Commission, and a speaking fee and reimbursement for travel costs from Dräger, outside the submitted work.
- Received December 10, 2018.
- Accepted May 1, 2019.
- Copyright ©ERS 2019
This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0.
